I can see why people would want to hide a sub as they take up a lot of space but do you think an in-wall sub can ever really rock as hard as a self contained unit.

Personally, I use a pair of PSB subs in my living room system and they go pretty low. The cool part about them is they have their own enclosrures however they don't come anywhere close to the depths of my Revel Sub 30 in my big theater however they do REALLY nicely round out the depth of music in my living room. People don't know there are subs in the wall but they know the music sounds "full".

Ultimately, I would like to add a Bel Canto amp and some form of EQ for the living room system so I can have Bob Hodas come and tune the system for me. i have no idea how it measures but I do know I listen in there more than I do in the big theater.